Field of the Disclosure
The present disclosure relates to communications systems and more specifically to linear path protection in a centralized controller environment.
Description of the Related Art
A communication network may include network elements that route packets through the network. Some network elements may include a distributed architecture, wherein packet processing may be distributed among several subsystems of the network element (e.g., line cards). Thus, network elements may be modular and may include various subsystems and/or subelements, which may be represented as logical and/or physical entities. The logical and/or physical entities included in a network element may refer to the network element, a shelf, a slot, a port, a channel and/or various combinations thereof.
Throughout the network, linear point-to-point paths between two network elements may be provisioned for carrying network traffic. A primary linear point-to-point path, referred to as a “working path” may be protected with a “protect path” that is a secondary or redundant path between the same network endpoints. In the event of a failure of the working path, for example, a protection switch may be performed to switch from the working path to the protect path, thereby maintaining network service between the endpoints.
Furthermore, software-defined networking (SDN) represents an important step towards network virtualization and/or abstraction and may allow for a logical network entity to be instantiated automatically using software instructions, rather than manually from user input. In this manner, SDN may enable flexible definition of virtual networks. For example, using the OpenFlow communications protocol managed by The Open Network Foundation (ONF) to implement SDN, a traffic flow entity may be instantiated using an arbitrary combination of layer identifiers defined in a header space. OpenFlow may use various combinations of traffic identifiers (Internet-protocol (IP) addresses, media access controller (MAC) addresses, port addresses, etc.) at various layers to define a traffic flow. Then, by installing and configuring packet-forwarding rules associated with the flow to network elements, an OpenFlow controller may ensure that the traffic flow entity instantiates a path that is routed through a network including the corresponding network elements.
In an SDN environment with a central controller, linear point-to-point protection switching, when implemented and controlled by the central controller, may take substantially more time to execute than is desirable for carrier-class network services, at least in part due to communication overhead between the central controller and the respective network element endpoints.